Molecular basis of androgen receptor mediated gene transcriptional repression

雄激素受体介导的基因转录抑制的分子基础

• 批准号: 9068848
• 负责人: Changmeng Cai
• 金额: $ 24.22万
• 依托单位: UNIVERSITY OF MASSACHUSETTS BOSTON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9068848
• 关键词: Affect; Androgen Receptor; Androgens; Binding; Binding Sites; Bioinformatics; CYP17A1 gene; Cancer Patient; Cell Cycle Progression; Cell Line; ChIP-seq; Chromatin; Clinical; Complex; DNA biosynthesis; Data; Development; Disease; ETV1 gene; Elements; Epigenetic Process; Feedback; Funding; Gene Amplification; Gene Chips; Gene Expression; Gene Expression Regulation; Genes; Genetic Transcription; Goals; Grant; Health; Histones; Homeostasis; Introns; Israel; JUN gene; Lead; Ligands; Lysine; Malignant Neoplasms; Malignant neoplasm of prostate; Mediating; Medical center; Mentors; Messenger RNA; Modification; Molecular; Pathway Analysis; Pathway interactions; Patients; Phase; Phosphorylation; Phosphotransferases; Physiological; Play; Prostate; Prostate Cancer therapy; Publishing; Receptor Activation; Receptor Gene; Receptor Signaling; Recruitment Activity; Regulation; Relapse; Repression; Research; Resistance; Resistance development; Role; Signal Transduction; Site; Source; Study models; Substrate Specificity; Synthetic Genes; TMPRSS2 gene; Transactivation; Transcription Repressor/Corepressor; Translating; United States National Institutes of Health; Universities; Work; Xenograft Model; base; cancer initiation; castration resistant prostate cancer; clinically relevant; cooperative study; deprivation; field study; fusion gene; gene repression; genome-wide; mRNA Expression; medical schools; next generation sequencing; novel; novel strategies; post-doctoral training; pre-doctoral; prevent; programs; prostate cancer cell; receptor binding; receptor expression; receptor function; transcription factor; transcriptome sequencing; tumor; tumor progression; whole genome

DESCRIPTION (provided by applicant): In my pre-doctoral study, I worked with Dr. Lirim Shemshedini (University of Toledo) on studying gene regulation by androgen receptor (AR) in prostate cancer (PCa). I have published the results on studying the cooperative role of c-Jun on AR transactivation and the roles of AR regulated SGCα1, ETV1, and MRP4 genes in PCa. In my postdoctoral training, I joined Steven Balk lab at Beth Israel Deaconess Medical Center (BIDMC)/Harvard Medical School and focused on understanding roles of AR in the lethal form of PCa (CRPC) that develops the resistance to androgen deprivation therapy (ADT). Research in the Balk lab is focused on PCa and AR, and the lab has funding from multiple sources including NIH R01 support, a Prostate Cancer SPORE, DoD Prostate Cancer program, and PCF challenge grant. My initial study is on studying the crosstalk of AR and HER signaling and then I moved to the field of studying TMPRSS2:ERG fusion gene in PCa. Using fusion positive cell lines, I have established xenograft models that clearly mimic the progression of CRPC. Studying this model led to three major findings: (1) SOX9 was identified as the major downstream effector of TMPRSS2:ERG in fusion positive PCa; (2) increased intratumoal androgen synthesis mediates tumor resistance to ADT and CYP17A1 inhibition; (3) increased AR expression in CRPC is due to relieving AR suppression of its own gene. AR plays a pivotal role in primary PCa and regains its functions in CRPC. In contrast to the wellestablished AR activation function on gene transcription, its suppression function is poorly understood. This proposal mainly focuses on elucidating the molecular mechanisms of AR mediated gene transcriptional repression. My immediate goal of 2-yrs mentored phase will be to pursue the molecular basis and clinical relevance of AR mediated its own gene expression through binding of its intron 2 site (ARBS2) and repressing the gene transcription. Several other AR-repressed gene loci that mediate expression of androgen synthetic genes (HSD17B6 and AKR1C3) will also be studied. In particularly, the repressor complex on chromatin and their actions that results in the epigenetic modifications on ARBS2 and regulates its activity will be identified. More important, any distinct mechanism that separates AR as an activator versus a repressor needs to be elucidated. These findings will also be translated into clinical therapy to enhance the activity of ARBS2 but not affect AR activated gene loci. For the long-term goal, which includes the 3-yr independence phase, the findings on AR gene loci will be extended to the whole genome of PCa cells. Taking the advantages of next generation sequencing and bioinformatics analysis on high throughput data, the global AR-mediated suppressor elements will be identified in PCa cells and their functions will also be studied. Moreover, the global roles of AR interacted repressor complex on gene transcription and on prostate cancer initiation and progression will also be studied in the phase of proposal. Current findings clearly demonstrate that we do not yet fully understand how AR functions, and that further novel mechanisms of action may contribute to its regulation of subsets of genes. As AR regulates a large number of genes involved in many cellular pathways, the potential ability to selectively target subsets of these genes has broad implications for the therapy of PCa and other diseases.

描述（由申请人提供）： 在我的博士预科学习中，我与Lirim Shemshedini博士（托莱多大学）合作研究基因 前列腺癌（PCa）中雄激素受体（AR）的调节。我已经发表了研究c-Jun对AR反式激活的协同作用以及AR调控的SGCα1、ETV 1和MRP 4基因在PCa中的作用的结果。在我的博士后培训中，我加入了Beth Israel Deaconess Medical Center（BIDMC）/哈佛医学院的Steven Balk实验室，并专注于了解AR在致命形式的PCa（CRPC）中的作用，该形式对雄激素剥夺疗法（ADT）产生抗性。Balk实验室的研究重点是PCa和AR，该实验室拥有多个来源的资金，包括NIH R 01支持，前列腺癌SPORE，DoD前列腺癌计划和PCF挑战补助金。我最初的研究是在AR和HER信号通路的相互作用，然后我转移到研究前列腺癌中的TMPRSS 2：ERG融合基因的领域。使用融合阳性细胞系，我已经建立了异种移植模型，清楚地模拟CRPC的进展。研究该模型得到三个主要发现：（1）在融合阳性PCa中，SOX 9被鉴定为TMPRSS 2：ERG的主要下游效应物;（2）增加的体内雄激素合成介导肿瘤对ADT和CYP 17 A1抑制的抗性;（3）CRPC中AR表达增加是由于缓解其自身基因的AR抑制。AR在原发性PCa中起关键作用，并在CRPC中恢复其功能。与AR对基因转录的激活功能相比，其抑制功能知之甚少。本研究主要致力于阐明AR介导的基因转录抑制的分子机制。我的2年指导阶段的直接目标将是追求AR通过其内含子2位点（ARBS 2）的结合和抑制基因转录介导其自身基因表达的分子基础和临床相关性。还将研究其他几个介导雄激素合成基因（HSD 17 B6和AKR 1C 3）表达的AR抑制基因位点。特别是，将鉴定染色质上的阻遏物复合物及其导致ARBS 2表观遗传修饰并调节其活性的作用。更重要的是，任何不同的机制，区分AR作为激活剂与阻遏物需要阐明。这些发现也将转化为临床治疗，以增强ARBS 2的活性，但不影响AR激活的基因位点。对于包括3年独立阶段的长期目标，AR基因位点的发现将扩展到PCa细胞的整个基因组。利用下一代测序技术和生物信息学分析技术，对前列腺癌细胞中AR介导的抑制因子进行鉴定，并对其功能进行研究。此外，AR相互作用的阻遏物复合物在基因转录和前列腺癌的发生和发展中的整体作用也将在提案阶段进行研究。目前的研究结果清楚地表明，我们还没有完全了解AR的功能，进一步的新的作用机制可能有助于其对基因子集的调节。由于AR调节参与许多细胞途径的大量基因，因此选择性靶向这些基因子集的潜在能力对PCa和其他疾病的治疗具有广泛的意义。